Chronic morphine drives adaptations in synaptic transmission thought to underlie opiate dependence. Here we examine the role of micro-opioid receptor (MOR) trafficking in one of these adaptations, specifically, changes in GABA transmission in the ventral tegmental area (VTA). To address this question, we used a knock-in mouse, RMOR (for recycling MOR), in which genetic change in the MOR promote...

Extensive 3' alternative splicing of the mu opioid receptor gene OPRM1 creates multiple C-terminal splice variants. However, their behavioral relevance remains unknown. The present study generated 3 mutant mouse models with truncated C termini in 2 different mouse strains, C57BL/6J (B6) and 129/SvEv (129). One mouse truncated all C termini downstream of Oprm1 exon 3 (mE3M mice), while the other...

Effect of Otostegia persica on naloxone-induced morphine withdrawal syndrome was studied in male mice. Dependence was induced using daily subcutaneous injections of morphine for three days. Morphine was injected to mice at doses of 30 and 45mg/kg on day 1 and 60 and 90mg/kg on day 2 (8:00 am and 6:00 pm). On day 3, morphine (90mg/kg) was injected 1h before oral administration and 1.5h before in...

The mechanisms of drug dependence and rewarding properties of opiates are not exactly known and several neurotransmitters seem to be involved. It is possible that the rennin-angiotensin system could interact with the opioid system, since it has been shown that angiotensin II(Ang) and ACE inhibitors have analgesic, anticonvulsant and antidepression effects and in some cases they could antagonize...

background: chronic administration of morphine cause physical dependence but the exact mechanism of this phenomenon remains unclear. the aim of this study is the assessment of systemic and intracerebroventricular (icv) administration of ramelteon (a melatonin receptor agonist) on morphine physical dependence. methods: 88 adult male rats were divided into 2 major groups, namely “systematic” and ...

In drug-free subjects, a single dose of morphine followed by an opioid antagonist a few hours later results in signs of a withdrawal syndrome, suggesting a state of physical dependence. Increased urination/defecation, altered startle, and ultrasonic vocalizations (USV) are some signs of the withdrawal syndrome in rats chronically dependent on morphine. We investigated whether naltrexone stimula...

PURPOSE There are several reports about effects of Salvia spp. on CNS. The present experiment is undertaken to study effect of S. limbata, S. hypoleuca and S. macrosiphon on withdrawal syndrome in mice. METHODS Antinociceptive activities of aerial parts of Salvia spp. is investigated using hot plate method. In addition, the effect of its aerial parts on morphine dependence is investigated in ...

Introduction: It has been reported that oral morphine dependency facilitated formation of spatial learning and memory. In the present study the role of NMDA receptors located in hippocampal CA1 area of morphine dependent rats was studied. Methods: Male rats were divided into 4 groups. Two cannulae were stereotaxically implanted bilaterally into the hippocampal CA1 area. After 5 days recover...

To explore the effect of sinomenine on the nitric oxide (NO)/neural nitric oxide synthase (nNOS) system in the cerebellum and spinal cord of morphine-dependent and morphine-withdrawal Kunming mice, mice were subjected to injection of morphine with an increasing dose for 5 d, and then were treated with sinomenine (40 mg/kg, i.p.) for another 5 d. Naloxone was used to develop acute withdrawal, an...

Elevation of plasma corticosterone (PCS) has been used as an indicator of morphine withdrawal, but it is not clear whether the magnitude of elevation is related to the intensity of the dependence. The dose-dependent effects of naloxone on PCS and body weight were studied in male Sprague-Dawley rats rendered physically dependent on morphine by injecting increasing doses of 40-120 mg/kg/day, s.c....